The present invention disclosed herein relates to a resonator and a biosensor system including the resonator.
Typically, existing biosensors may be divided into two categories in terms of their use scope: one is applied to detect a quantitative bio-signal, and the other one is applied to determine whether the specific substances exist or whether the specific reaction occurs. To improve the sensitivity or reaction sensitivity with respect to the biological specific substances, an indirect method has been used for measuring the specific substances or the reaction sensitivity, i.e., various light, electricity, and magnetic markers are combined to an antibody to measure the markers through reaction with the antibody coupled to the biosensor through the antigen.
In the case of the method using a light sensor, it is convenient in that the reaction can be directly seen through the naked eye. However, for more sensitive detection, large-scaled equipment is required. Also, in the case of the method for measuring electrical properties (impedances) by using gold nano particles, there is difficulty in that an accurate sensor for the biosensor should be manufactured.
Generally, there are three methods for a biosensor system using a magnetic bead as a marker. The first method is a method for measuring an inductance change of an air-core coil inductor. The second method is a method for very accurately measuring a magnetic moment of a magnetic bead by using a superconducting quantum interference device (SQUID) that is an existing accurate magnetic measuring system. The third method is a method using a giant magnetoresistance device. Among these, in consideration of the efficiency and the economic feasibility, the first method is deemed as the most effective method for measuring a change of a permeability of a magnetic bead. However, a reasonable precondition in which a magnetic moment of a superparamagnetic bead should be large may be the most important factor for accurately measuring the change of the permeability. Also, in addition to the above-described method, studies are processing in two aspects. In the first aspect, various bridge circuits are realized in design of the measurement circuit. Also, in the second aspect, a measurement frequency increases to a high frequency.
Recently, a system for measuring an inductance change by using a magnetic bead may be generally realized within a frequency region of about several ten kHz to about several ten MHz. Also, the sensitivity of the biosensor increases through the change of the permeability in a frequency region of about several GHz.